In-plane switching LCD having interlayer insulator at particular region with respect to electrodes

ABSTRACT

There is provided a liquid crystal display including (a) a first substrate, (b) a second substrate spaced away from and facing the first substrate, (c) a liquid crystal layer sandwiched between the first and second substrates, (d) a first electrode formed on the first substrate at a surface facing the liquid crystal layer, (e) a second electrode formed on the first substrate at a surface facing the liquid crystal layer, and cooperating with the first electrode to form a pixel, the first and second electrodes generating an electric field therebetween to thereby implement in-plane switching, and (f) an interlayer insulating film formed at least below the second electrode, but not formed at least below the first electrode, a dielectric layer formed between at least a part of an upper surface of the first electrode and the liquid crystal layer being designed to have a capacitance per a unit area, almost equal to a capacitance per a unit area of a dielectric layer formed between at least a part of an upper surface and the liquid crystal layer. In the above-mentioned liquid crystal display, since a dielectric distance between the first electrode and the liquid crystal layer is almost equal to a dielectric distance between the second electrode and the liquid crystal layer, it is possible to balance flexo-electric effects on the first and second electrodes, which ensures suppression in generation of after-images.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a liquid crystal display and a method offabricating the same, and more particularly to a liquid crystal displayimplementing in-plane switching where an electric field to be applied toliquid crystal is generated in a plane parallel to a substrate, and amethod of fabricating the same.

2. Description of the Related Art

A conventional liquid crystal display having employed twisted nematic isaccompanied with a problem of a narrow viewing angle. In order to solvethis problem, there has been suggested an in-plane switching (IPS) typeliquid crystal display in which an electric field to be applied toliquid crystal is generated in a plane parallel to a substrate.

An in-plane switching type liquid crystal display is suggested, forinstance, in Japanese Unexamined Patent Publications Nos. 7-128683,7-159786, and 8-220518.

FIG. 1 is a top plan view of an in-plane switching type liquid crystaldisplay suggested in Japanese Unexamined Patent Publication No.7-128683, FIG. 2 is a cross-sectional view taken along the line II--IIin FIG. 1, and FIG. 3 is a cross-sectional view of the in-planeswitching type liquid crystal display. Each of FIGS. 1 to 3 illustratesa pixel positioned at an intersection of an image signal line 861 and ascanning line 862.

As illustrated in FIGS. 1 to 3, the illustrated liquid crystal displayis comprised of a substrate 810, a first comb-shaped electrode 801formed on the substrate 810 and composed of an electrically conductivelayer made of metal and so on, an interlayer insulating layer 811covering the first comb-shaped electrode 801 and the substrate 810therewith, a second comb-shaped electrode 802 formed on the interlayerinsulating layer 811 and composed of an electrically conductive layermade of metal and so on, an alignment layer 820 formed over the secondcomb-shaped electrode 802 and the interlayer insulating film 811 foraligning liquid crystal, an opposing substrate 840 formed with a colorlayer (not illustrated), black matrix (not illustrated) and so on, analignment layer 821 formed on a lower surface of the opposing substrate840 for aligning liquid crystal, a liquid crystal layer 830 sandwichedbetween the alignment layers 820 and 821, and a thin film transistor(TFT) 863 for driving liquid crystal.

As is understood in view of FIGS. 2 or 3, the first and secondcomb-shaped layers 801 and 802 are electrically conductive layers formedin separate fabrication steps. The first and second comb-shaped layers801 and 802 are separated from each other by the interlayer insulatingfilm 811.

In operation, when the scanning line 862 is selected, a voltage on theimage signal line 861 is transferred to the second comb-shaped electrode802 through the thin film transistor 863. As a result, an electric fieldis generated between the first and second comb-shaped electrodes 801 and802 in accordance with image data.

Liquid crystal molecules in the liquid crystal layer 830 are in advancealigned in a direction almost perpendicular to a plane of FIG. 3 by thealignment layers 820 and 821. These liquid crystal molecules areoriented in accordance with the electric field, as illustrated in FIG.3. Thus, there is implemented in-plane switching.

FIGS. 4 and 5 illustrate an in-plane switching type liquid crystaldisplay suggested in the above-mentioned Japanese Unexamined PatentPublication No. 7-128683. FIG. 4 is a top plane view of the liquidcrystal display, and FIG. 5 is a cross-sectional view taken along theline V--V in FIG. 4.

In the illustrated liquid crystal display, a common line 903 iselectrically connected to a first comb-shaped electrode 901 through acontact hole 904. Hence, the first comb-shaped electrode 901 and asecond comb-shaped electrode 902 are formed in a common electricallyconductive layer on a substrate 910. When a scanning line 962 isselected, a voltage on an image signal line 961 is transferred to asecond comb-shaped electrode 902 through a thin film transistor 963. Asa result, there is generated an electric field between the first andsecond electrodes 901 and 902. The thus generated electric fieldperforms in-plane switching.

In accordance with the liquid crystal display suggested in theabove-mentioned Publication, the first comb-shaped electrode 901 has thesame height as that of the second comb-shaped electrode 902, asillustrated in FIG. 5, ensuring enhancement in degree of parallelizationof an electric field performing in-plane switching.

The above-mentioned Japanese Unexamined Patent Publication No. 7159786has suggested a liquid crystal display in which an alignment layer andan insulating film are designed to have a smaller dielectric constantthan that of a liquid crystal layer to thereby generate an improvedhorizontal electric field, an insulating film and an alignment layer arecomposed of common material to thereby improve an efficiency offabrication process, and electric fields for in-plane switching are madeparallel.

The above-mentioned Japanese Unexamined Patent Publication No. 8220518has suggested a liquid crystal display in which recessed and raisedportions of a surface facing a liquid crystal layer are less formed tothereby ensure a higher contrast ratio.

However, with respect to display characteristics, an in-plane switchingtype liquid crystal display is accompanied with a problem ofafter-image, which is found also in a twisted nematic type liquidcrystal display, but in a smaller degree. The problem of after-image inan in-plane switching type liquid crystal display is pointed out also inthe above-mentioned Japanese Unexamined Patent Publication No. 7-157986.

It is said that such after-image is caused by electric charges residualat an alignment layer and/or at an interface between a substrate and aliquid crystal layer. It is considered that after-image is notgenerated, if liquid crystal is driven by an alternative current betweenfirst and second comb-shaped electrodes, and an absolute value of apositive voltage is substantially equal to an absolute value of anegative voltage in an alternative current.

However, the inventor of the present invention has found thatflexo-electric effect found on a comb-shaped electrode has a closeconnection with generation of after-image.

In general, if bar-shaped liquid crystal molecules are radially alignedor spray-aligned, there would be generated polarization between insideand outside of radial alignment configuration. This is calledflexo-electric effect. A degree of flexo-electric effect is dependent ona degree of extension of radial alignment configuration.

In the conventional liquid crystal display illustrated in FIGS. 1 to 3,whereas the interlayer insulating film 811 and the alignment layer 820are sandwiched between the first comb-shaped electrode 801 and theliquid crystal layer 830, only the alignment layer 820 is sandwichedbetween the second comb-shaped electrode 802 and the liquid crystallayer 830, as illustrated in FIG. 3.

In other words, a dielectric distance between an upper surface of thefirst comb-shaped electrode 801 and the liquid crystal layer 830 isdifferent from a dielectric distance between an upper surface of thesecond comb-shaped electrode 802 and the liquid crystal layer 830 by athickness of the interlayer insulating film 811. Herein, a dielectricdistance is defined as a capacitance per a unit area, obtained whensandwiched between imaginary electrodes.

As a result, a degree of extension in radial configuration of alignmentof liquid crystal in the vicinity of the alignment layer 820 just abovethe first comb-shaped electrode 801 is different from the same in thevicinity of the alignment layer 820 just above the second comb-shapedelectrode 802. Liquid crystal generates flexo-electric effect independence of the radial configuration, and polarize. It is consideredthat if the radial configuration of liquid crystal above the firstcomb-shaped electrode 801 is identical with the radial configuration ofliquid crystal above the second comb-shaped electrode 802, polarizationof liquid crystal is balanced, and if electric charges are accumulatedon the first and second comb-shaped electrodes 801 and 802 to the samedegree, a voltage based on a direct current is not residual across thefirst and second comb-shaped electrodes 801 and 802, even after in-planeswitching has been stopped, which will not contribute to generation ofafter-image.

However, if the radial configuration of liquid crystal above the firstcomb-shaped electrode 801 has an extension in a different degree from anextension of the radial configuration of liquid crystal above the secondcomb-shaped electrode 802, polarization of liquid crystal is notbalanced. As a result, electric charges are residual in implementingin-plane switching, which would cause a problem of after-image.

In the liquid crystal display illustrated in FIGS. 4 and 5, the firstand second comb-shaped electrodes 901 and 902 are formed with nointerlayer insulating layer being formed therebetween, and hence, can beformed in a common film-forming step. However, as illustrated in FIG. 6,in a photolithography step for forming an electrically conductive layerfrom which the first and second comb-shaped electrodes 901 and 902 areformed, a patterning defect 970 might occur because of etching residueor inaccuracy in photolithography. If the patterning defect 970 asillustrated in FIG. 6 occurs, the first comb-shaped electrode 901 wouldbe readily short-circuited with the second comb-shaped electrode 902.

That is, the liquid crystal display illustrated in FIGS. 4 and 5 canadvantageously suppress generation of after-image, but is accompaniedwith a problem of reduction in a fabrication yield, as mentioned above.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a liquid crystaldisplay and a method of fabricating the same, both of which are capableof suppressing generation of after-image caused by imbalance inflexo-electric effect originated from two comb-shaped electrodes, andenhancing a yield of fabricating liquid crystal display.

In one aspect of the present invention, there is provided a liquidcrystal display including (a) a first substrate, (b) a second substratespaced away from and facing the first substrate, (c) a liquid crystallayer sandwiched between the first and second substrates, (d) a firstelectrode formed on the first substrate at a surface facing the liquidcrystal layer, (e) a second electrode formed on the first substrate at asurface facing the liquid crystal layer, and cooperating with the firstelectrode to form a pixel, the first and second electrodes generating anelectric field therebetween to thereby implement in-plane switching, and(f) an interlayer insulating film formed at least below the secondelectrode, but not formed at least below the first electrode, adielectric layer formed between at least a part of an upper surface ofthe first electrode and the liquid crystal layer being designed to havea capacitance per a unit area, almost equal to a capacitance per a unitarea of a dielectric layer formed between at least a part of an uppersurface and the liquid crystal layer.

It is preferable that the interlayer insulating film covers the firstelectrode therewith, and that the interlayer insulating film is designedto have a first thickness on an upper surface of the first electrode anda second thickness below the second electrode, the first thickness beingsmaller than the second thickness.

It is also preferable that the interlayer insulating film is designed tohave a third thickness in a region other than a region located below thesecond electrode, the third thickness being smaller than the secondthickness.

It is preferable that the interlayer insulating film is formed only in aregion other than an upper surface of the first electrode.

The second electrode may be covered with an anodic oxide film.

It is preferable that the liquid crystal display may further include acover insulating film covering the first and second electrodestherewith.

It is preferable that an upper surface of the first electrodes isexposed. It is also preferable that upper and side surfaces of the firstelectrode are exposed.

There is further provided a liquid crystal display including (a) a firstsubstrate, (b) a second substrate spaced away from and facing the firstsubstrate, (c) a liquid crystal layer sandwiched between the first andsecond substrates, (d) a first electrode formed on the first substrateat a surface facing the liquid crystal layer, (e) a second electrodeformed on the first substrate at a surface facing the liquid crystallayer, and cooperating with the first electrode to form a pixel, thefirst and second electrodes generating an electric field therebetween tothereby implement in-plane switching, (f) an interlayer insulating filmformed at least below the second electrode and over the first electrode,and (g) a flexo-electric relieving layer composed of electricallyinsulating material and formed on the second electrode, a dielectriclayer formed between at least a part of an upper surface of the firstelectrode and the liquid crystal layer being designed to have acapacitance per a unit area, almost equal to a capacitance per a unitarea of a dielectric layer formed between at least a part of an uppersurface and the liquid crystal layer.

It is preferable that the flexo-electric relieving layer is almostcoextensive with the second electrode.

It is also preferable that the flexo-electric relieving layer has thesame thickness as a thickness of the interlayer insulating layer formedon the first electrode.

It is preferable that the flexo-electric relieving layer has a ratio ofa thickness to a dielectric constant, which ratio is almost equal to aratio of a thickness to a dielectric constant, of the interlayerinsulating layer.

There is still further provided a liquid crystal display including (a) afirst substrate formed at an upper surface thereof with at least onerecessed portion, (b) a second substrate spaced away from and facing thefirst substrate, (c) a liquid crystal layer sandwiched between the firstand second substrates, (d) a first electrode formed on the firstsubstrate at a surface facing the liquid crystal layer, (e) a secondelectrode formed on the first substrate at a surface facing the liquidcrystal layer, and cooperating with the first electrode to form a pixel,the first and second electrodes generating an electric fieldtherebetween to thereby implement in-plane switching, at least a part ofthe second electrode being formed in the recessed portion of the firstelectrode, and (f) an interlayer insulating film formed at least belowthe second electrode, but not formed at least below the first electrode,a dielectric layer formed between at least a part of an upper surface ofthe first electrode and the liquid crystal layer being designed to havea capacitance per a unit area, almost equal to a capacitance per a unitarea of a dielectric layer formed between at least a part of an uppersurface and the liquid crystal layer.

The liquid crystal display may further include an insulating film formedon the first substrate, in which case, the recessed portion is formed ata surface of the insulating film.

It is preferable that the liquid crystal display may further include aflat insulating film covering the first and second electrodes.

For instance, the flat insulating film may be formed by applying ontothe first and second electrodes and baking. The flat insulating film maybe composed predominantly of organic polymer.

The flat insulating film may be used as an alignment layer.

The liquid crystal display may further include a flexo-electricrelieving layer composed of electrically insulating material and formedon the second electrode.

There is yet further provided a liquid crystal display including (a) afirst substrate formed at an upper surface thereof with at least oneraised portion, (b) a second substrate spaced away from and facing thefirst substrate, (c) a liquid crystal layer sandwiched between the firstand second substrates, (d) a first electrode formed on the firstsubstrate at a surface facing the liquid crystal layer, at least a partof the first electrode being formed on the raised portion, (e) a secondelectrode formed on the first substrate at a surface facing the liquidcrystal layer, and cooperating with the first electrode to form a pixel,the first and second electrodes generating an electric fieldtherebetween to thereby implement in-plane switching, and (f) aninterlayer insulating film formed at least below the second electrode,but not formed at least below the first electrode, a dielectric layerformed between at least a part of an upper surface of the firstelectrode and the liquid crystal layer being designed to have acapacitance per a unit area, almost equal to a capacitance per a unitarea of a dielectric layer formed between at least a part of an uppersurface and the liquid crystal layer.

The liquid crystal may further include an insulating film formed on thefirst substrate, in which case, the recessed portion is formed at asurface of the insulating film.

The liquid crystal display may further include a flexo-electricrelieving layer composed of electrically insulating material and formedon the second electrode.

In another aspect of the present invention, there is provided a methodof fabricating a liquid crystal display including (a) a first substrate,(b) a second substrate spaced away from and facing the first substrate,(c) a liquid crystal layer sandwiched between the first and secondsubstrates, (d) a first electrode formed on the first substrate at asurface facing the liquid crystal layer, and (e) a second electrodeformed on the first substrate at a surface facing the liquid crystallayer, and cooperating with the first electrode to form a pixel, thefirst and second electrodes generating an electric field therebetween tothereby implement in-plane switching, the method including the steps, insequence, of (a) forming a first metal layer on the first substrate, (b)patterning the first metal layer into a first electrode, (c) coveringthe first electrode with an interlayer insulating layer, (d) forming asecond metal layer on the interlayer insulating layer, (e) forming aninsulating layer on the second metal layer, and (f) patterning thesecond metal layer and the insulating layer into the second electrodeand a flexo-electric relieving layer almost coextensive with the secondelectrode.

The liquid crystal display may further include an insulating film formedon the first substrate, in which case, the first metal layer is formedon the insulating film.

There is further provided a method of fabricating a liquid crystaldisplay including (a) a first substrate, (b) a second substrate spacedaway from and facing the first substrate, (c) a liquid crystal layersandwiched between the first and second substrates, (d) a firstelectrode formed on the first substrate at a surface facing the liquidcrystal layer, and (e) a second electrode formed on the first substrateat a surface facing the liquid crystal layer, and cooperating with thefirst electrode to form a pixel, the first and second electrodesgenerating an electric field therebetween to thereby implement in-planeswitching, the method including the steps, in sequence, of (a) forming afirst metal layer on the first substrate, (b) patterning the first metallayer into a first electrode, (c) covering the first electrode with aninterlayer insulating layer, (d) forming a second metal layer on theinterlayer insulating layer, and (e) etching both the second metal layerand the interlayer insulating layer to thereby pattern both the secondmetal layer and the interlayer insulating layer into the secondelectrode, and thin or remove the interlayer insulating layer in aregion other than a region located below the second electrode.

There is still further provided a method of fabricating a liquid crystaldisplay including (a) a first substrate, (b) a second substrate spacedaway from and facing the first substrate, (c) a liquid crystal layersandwiched between the first and second substrates, (d) a firstelectrode formed on the first substrate at a surface facing the liquidcrystal layer, and (e) a second electrode formed on the first substrateat a surface facing the liquid crystal layer, and cooperating with thefirst electrode to form a pixel, the first and second electrodesgenerating an electric field therebetween to thereby implement in-planeswitching, the method including the steps, in sequence, of (a) forming arecessed portion at a surface of the first substrate, (b) forming afirst metal layer on the first substrate, (c) patterning the first metallayer into a first electrode on a surface of the first electrode, (d)covering the first electrode with an interlayer insulating layer, (e)forming a second metal layer on the interlayer insulating layer, and (f)patterning the second metal layer into the second electrode in therecessed portion of the first substrate.

There is yet further provided a method of fabricating a liquid crystaldisplay including (a) a first substrate, (b) a second substrate spacedaway from and facing the first substrate, (c) a liquid crystal layersandwiched between the first and second substrates, (d) a firstelectrode formed on the first substrate at a surface facing the liquidcrystal layer, and (e) a second electrode formed on the first substrateat a surface facing the liquid crystal layer, and cooperating with thefirst electrode to form a pixel, the first and second electrodesgenerating an electric field therebetween to thereby implement in-planeswitching, the method including the steps, in sequence, of (a) forming araised portion at a surface of the first substrate, (b) forming a firstmetal layer on the raised portion of the first substrate, (c) patterningthe first metal layer into a first electrode, (d) covering the firstelectrode with an interlayer insulating layer, (e) forming a secondmetal layer on the interlayer insulating layer, and (f) patterning thesecond metal layer into the second electrode above a region other than aregion where the raised portion is formed.

In accordance with the above-mentioned liquid crystal display, adielectric distance between the first electrode and the liquid crystallayer is designed to be almost equal to a dielectric distance betweenthe second electrode and the liquid crystal layer. Hence, it is possibleto keep flexo-electric effects on the first and second electrodesbalanced, which ensures suppression in generation of after-image.

Since the interlayer insulating film electrically insulates the firstand second electrodes from each other, it is possible to avoid the firstand second electrodes from being short-circuited due to a patterningdefect, ensuring a higher fabrication yield.

In accordance with the above-mentioned methods, it is possible tofabricate the above-mentioned liquid crystal display. In addition, sincethe second electrode and the flexo-electric relieving layer are formedin a common step, or since the second electrode is formed in a step inwhich the interlayer insulating film is also thinned or removed, it ispossible to shorten a process of fabricating a liquid crystal display.

The above and other objects and advantageous features of the presentinvention will be made apparent from the following description made withreference to the accompanying drawings, in which like referencecharacters designate the same or similar parts throughout the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a pixel in a first conventional liquidcrystal display.

FIG. 2 is a cross-sectional view taken along the line II--II in FIG. 1.

FIG. 3 is a cross-sectional view of the first conventional liquidcrystal display.

FIG. 4 is a top plan view of a pixel in a second conventional liquidcrystal display.

FIG. 5 is a cross-sectional view taken along the line V--V in FIG. 4.

FIG. 6 is a cross-sectional view of the second conventional liquidcrystal display.

FIG. 7 is a top plan view of a pixel in a liquid crystal display inaccordance with the first embodiment.

FIG. 8 is a cross-sectional view taken along the line VIII--VIII in FIG.7.

FIG. 9 is a cross-sectional view of the liquid crystal display inaccordance with the first embodiment.

FIG. 10 is a top plan view of a pixel in a liquid crystal display inaccordance with the second embodiment.

FIG. 11 is a cross-sectional view taken along the line X--X in FIG. 10.

FIG. 12 is a top plan view of a pixel in a liquid crystal display inaccordance with the third embodiment.

FIG. 13A is a cross-sectional view taken along the line XIII--XIII inFIG. 12, illustrating a step in a method of fabricating the liquidcrystal display in accordance with the third embodiment.

FIGS. 13B to 13E are cross-sectional views taken along the lineXIII--XIII in FIG. 12, illustrating possible structures of the liquidcrystal display in accordance with the third embodiment.

FIG. 14 is a top plan view of a pixel in a liquid crystal display inaccordance with the fourth embodiment.

FIG. 15A is a cross-sectional view taken along the line XV--XV in FIG.14, illustrating a step in a method of fabricating the liquid crystaldisplay in accordance with the fourth embodiment.

FIGS. 15B to 15D are cross-sectional views taken along the line XV--XVin FIG. 14, illustrating possible structures of the liquid crystaldisplay in accordance with the fourth embodiment.

FIG. 16 is a top plan view of a pixel in a liquid crystal display inaccordance with the fifth embodiment.

FIG. 17 is a cross-sectional view taken along the line XVII--XVII inFIG. 16.

FIG. 18A is a cross-sectional view of a liquid crystal display inaccordance with the sixth embodiment, illustrating a step in a method offabricating the same.

FIGS. 18B to 18F are cross-sectional views of the liquid crystal displayin accordance with the sixth embodiment, illustrating possiblestructures of the same.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[First Embodiment]

FIGS. 7 to 9 illustrate a liquid crystal display in accordance with thefirst embodiment. FIG. 7 is a top plan view of a pixel in the liquidcrystal display, FIG. 8 is a cross-sectional view taken along the lineVIII--VIII in FIG. 7, and FIG. 9 is a cross-sectional view of the liquidcrystal display in accordance with the first embodiment. FIGS. 7 to 9illustrate a pixel located at an intersection of an image signal line161 and a scanning line 162.

As illustrated in FIGS. 7 to 9, the liquid crystal display in accordancewith the first embodiment is comprised of a substrate 110, a firstcomb-shaped electrode 101 formed on the substrate 110 and composed of anelectrically conductive layer made of metal and so on, an interlayerinsulating layer 111 covering the first comb-shaped electrode 101 andthe substrate 110 therewith, a second comb-shaped electrode 102 formedon the interlayer insulating layer 111 and composed of an electricallyconductive layer made of metal and so on, a flexo-electric relievinglayer 103 formed on the second comb-shaped electrode 102, an alignmentlayer 120 formed over the flexo-electric relieving layer 103 and theinterlayer insulating film 111 for aligning liquid crystal, an opposingsubstrate 140 formed with a color layer (not illustrated), black matrix(not illustrated) and so on, an alignment layer 121 formed on a lowersurface of the opposing substrate 140 for aligning liquid crystal, aliquid crystal layer 130 sandwiched between the alignment layers 120 and121, and a thin film transistor (TFT) 163 for driving liquid crystal.

In operation of the liquid crystal display in accordance with the firstembodiment, when the scanning line 162 is selected, a voltage on theimage signal line 161 is transferred to the second comb-shaped electrode102 through the thin film transistor 163. As a result, in-planeswitching is performed between the second comb-shaped electrode 102 andthe first comb-shaped electrode 101 to which a common voltage isapplied.

The thin film transistor 163 is a so-called bottom gate type thin filmtransistor in which a scanning line or a gate electrode 162 is locatedbelow an image signal line 161.

The first comb-shaped electrode 101, the second comb-shaped electrode102, the image signal line 161, and the scanning line 162 are allcomposed of an electrically conductive layer made of metal. The firstcomb-shaped layer 101 and the scanning line 162 are formed in a commonelectrically conductive layer. As illustrated in FIG. 8, the secondcomb-shaped electrode 102 and the image signal line 161 are formed in acommon electrically conductive layer.

With reference to FIG. 7, the first comb-shaped electrode 101 isdesigned to have common bus sections at both the left and upper end andthe right and upper end in FIG. 7 for connecting to first comb-shapedelectrodes of adjacent pixels.

With reference to FIG. 8, an electrically conductive layer constitutingthe first comb-shaped electrode 101 is formed directly on the substrate110. The substrate 110 is composed of glass, insulator, and so on. Thesubstrate 110 may be formed at a surface thereof with an insulatingfilm, in which case, the first comb-shaped electrode 101 is formed onthe insulating film.

The interlayer insulating film 111 is formed covering the firstcomb-shaped electrode 101 and the substrate 110 therewith. On theinterlayer insulating film 111 is formed an electrically conductivelayer constituting the second comb-shaped electrode 102 and the imagesignal line 161.

The flexo-electric relieving layer 103 composed of an insulating film isformed on the second comb-shaped electrode 102 so that theflexo-electric relieving layer 103 just overlaps the second comb-shapedelectrode 102. That is, the flexo-electric relieving layer 103 is almostcoextensive with the second comb-shaped electrode 102.

In the first embodiment, the flexo-electric relieving layer 103 isdesigned to have a thickness equal to a thickness of the interlayerinsulating film 111 formed on the first comb-shaped electrode 101.

Hereinbelow is explained a method of fabricating a liquid crystaldisplay in accordance with the above-mentioned first embodiment.

First, a metal film composed of, for instance, chromium is deposited onthe substrate 110 by means of a sputtering apparatus. The substrate 110may be formed at a surface thereof with an insulating film, in whichcase, a metal film is deposited on the insulating film.

Then, the metal film is patterned into the first comb-shaped electrode101 and the scanning line 162 in a photo-mask step comprising aphotolithography step and a plasma-etching step.

Then, the interlayer insulating film 111 is deposited over the firstcomb-shaped electrode 111 and the substrate 110 by plasma-enhancedchemical vapor deposition (PCVD). The interlayer insulating film 111 iscomposed of, for instance, silicon oxide or silicon nitride.

Then, the thin film transistor 163 and ohmic layers necessary for anoperation of the thin film transistor 163 are formed.

Then, an electrically conductive film composed of metal such aschromium, which will constitute the second comb-shaped electrode 102,and an insulating film composed of, for instance, silicon oxide orsilicon nitride, which will constitute the flexo-electric relievinglayer 103 are successively deposited by sputtering and plasma-enhancedchemical vapor deposition. Then, the thus formed electrically conductivefilm and insulating film are successively patterned into the secondcomb-shaped electrode 102 and the flexo-electric relieving layer 103,respectively, in a photo-mask step comprised of a photolithography stepand an etching step.

The flexo-electric relieving layer 103 may be first formed by patterningonly the insulating film in a photo-mask step and removing photoresist,and then, the second comb-shaped electrode 102 may be formed by etchingthe electrically conductive film with the already formed flexo-electricrelieving layer 103 being used as a mask.

In accordance with the above-mentioned method, the flexo-electricrelieving layer 103 is formed also on the image signal line 161, asillustrated in FIG. 8. Though the thus formed flexo-electric relievinglayer 103 does not directly contribute to balancing flexo-electriceffect, the flexo-electric relieving layer 103 provides an advantagethat while other pixel rows are being scanned, voltage noises generatedfrom the image signal line 161 are prevented from being exerted on theother pixel rows.

A cover insulating film (not illustrated) may be formed coveringtherewith upper and side surfaces of the flexo-electric relieving layer103, a side surface of the second comb-shaped electrode 102, and asurface of the interlayer insulating film 111.

A cell illustrated in FIG. 9 is fabricated using a product having theabove-mentioned structure. As illustrated in FIG. 9, the alignment film120 is formed on an upper surface of the product having theabove-mentioned structure. Similarly, the alignment film 121 is formedon a lower surface of the opposing substrate 140 having a color layer,black matrix and so on.

The liquid crystal layer 130 is sandwiched between the alignment films120 and 121. Liquid crystal molecules in the liquid crystal layer 130are in advance aligned in a direction almost perpendicular to a plane ofFIG. 9 by means of the alignment films 120 and 121. By generating anelectric field between the first comb-shaped electrode 101 and thesecond comb-shaped electrode 102, in-plane switching is performed in ahorizontal direction in a plane of FIG. 9.

As illustrated in FIG. 9, a degree of spread in radial configuration ofliquid crystal molecules in the vicinity of the alignment film 120 abovethe first comb-shaped electrode 101 is almost identical with the sameabove the second comb-shaped electrode 102. Accordingly, an intensity offlexo-electric effect generated above the first comb-shaped electrode101 is equal to an intensity of flexo-electric effect generated abovethe second comb-shaped electrode 102. In other words, the flexo-electriceffects generated above the first and second comb-shaped electrodes 101and 102 are balanced. Hence, even if in-plane switching is over, anamount of electric charges residual on the first comb-shaped electrode101 is almost equal to an amount of electric charges residual on thesecond comb-shaped electrode 102. As a result, a voltage based on adirect current is not residual, which ensures prevention of generationof after-image.

This is because the alignment film 120 and the interlayer insulatingfilm 111 are sandwiched between the first comb-shaped electrode 101 andthe liquid crystal layer 130, and the alignment film 120 and theflexo-electric relieving layer 103 are sandwiched between the secondcomb-shaped electrode 120 and the liquid crystal layer 130, whichensures that a dielectric distance of a dielectric layer formed betweenthe first comb-shaped electrode 101 and the liquid crystal layer 130 isapproximately equal to a dielectric distance of a dielectric layerformed between the second comb-shaped electrode 102 and the liquidcrystal layer 130. As mentioned earlier, a dielectric distance isdefined as a capacitance per a unit area, obtained when sandwichedbetween imaginary electrodes.

It is preferable that a ratio of a thickness to a dielectric constant inthe interlayer insulating layer 111 is equal to the same in theflexo-electric relieving layer 103. Even if the ratio is not commonbetween the interlayer insulating layer 111 and the flexo-electricrelieving layer 103, existence of the flexo-electric relieving layer 103ensures that the above-mentioned dielectric distances are approximatelyequal to each other with the result that flexo-electric effects foundabove the first and second comb-shaped electrodes 101 and 102 arebalanced to some degree.

In accordance with the first embodiment, since the interlayer insulatingfilm 111 electrically separates the first comb-shaped electrode 101 fromthe second comb-shaped electrode 102, even if the first or secondcomb-shaped electrode 101 or 102 includes patterning defects while aformation process thereof, it would be possible to avoid the first andsecond comb-shaped electrodes 101 and 102 from being short-circuited toeach other.

In addition, since the second comb-shaped electrode 102 and theflexo-electric relieving layer 103 can be formed in a common photo-maskstep, the liquid crystal display in accordance with the first embodimentcan be fabricated without an increase in fabrication steps in comparisonwith a conventional liquid crystal display including no flexo-electricrelieving layer 103.

[Second Embodiment]

FIGS. 10 and 11 illustrate a liquid crystal display in accordance withthe second embodiment. FIG. 10 is a top plan view of a pixel in theliquid crystal display, and FIG. 11 is a cross-sectional view takenalong the line XI--XI in FIG. 10. FIGS. 10 and 11 illustrate a pixellocated at an intersection of an image signal line 161a and a scanningline 162a.

As illustrated in FIGS. 10 and 11, the liquid crystal display inaccordance with the second embodiment is comprised of a substrate 110a,a first comb-shaped electrode 101a formed on the substrate 110a andcomposed of an electrically conductive layer made of metal, an imagesignal line 161a formed on the substrate 110a, an interlayer insulatinglayer 111a covering the first comb-shaped electrode 101a, the imagesignal line 161a, and the substrate 110a therewith, a second comb-shapedelectrode 102a formed on the interlayer insulating layer 111a andcomposed of an electrically conductive layer made of metal, aflexo-electric relieving layer 103a formed on the second comb-shapedelectrode 102a and composed of electrical insulator, an alignment layer(not illustrated) formed over the flexo-electric relieving layer 103aand the interlayer insulating film 111a for aligning liquid crystal, anopposing substrate (not illustrated), an alignment layer (notillustrated) formed on a lower surface of the opposing substrate foraligning liquid crystal, a liquid crystal layer (not illustrated)sandwiched between the alignment layers, and a thin film transistor(TFT) 163a for driving liquid crystal.

In operation of the liquid crystal display in accordance with the secondembodiment, when the scanning line 162a is selected, a voltage on theimage signal line 161a is transferred to the first comb-shaped electrode101a through the thin film transistor 163a. As a result, in-planeswitching is performed between the first comb-shaped electrode 101a andthe second comb-shaped electrode 102a to which a common voltage isapplied.

The thin film transistor 163a is a so-called top gate type thin filmtransistor in which a scanning line or a gate electrode 162a is locatedabove an image signal line 161a.

The functions performed by the first comb-shaped electrode 101a locatedat a lower layer and the second comb-shaped electrode 102a located at anupper layer in the second embodiment are exchanged in comparison withthe first embodiment with respect to an operation of a pixel. Whereas acommon voltage is applied to the first comb-shaped electrode 101 and animage signal is transferred to the second comb-shaped electrode 102 inthe first embodiment, a common voltage is applied to the secondcomb-shaped electrode 102a and an image signal is transferred to thefirst comb-shaped electrode 101a in the second embodiment.

However, the second embodiment provides the same advantageous effect asthat of the first embodiment. That is, the flexo-electric effects foundabove the first and second comb-shaped electrodes 101a and 102a arebalanced, similarly to the first embodiment.

[Third Embodiment]

FIGS. 12 and 13A to 13E illustrate a liquid crystal display inaccordance with the third embodiment. FIG. 12 is a top plan view of apixel in the liquid crystal display, FIG. 13A is a cross-sectional viewtaken along the line XIII--XIII in FIG. 12, illustrating a step in amethod of fabricating the liquid crystal display in accordance with thethird embodiment, and FIGS. 13B to 13E are cross-sectional views takenalong the line XIII--XIII in FIG. 12, illustrating possible structuresof the liquid crystal display in accordance with the third embodiment.

With reference to FIG. 12, when a scanning line 262 is selected, avoltage on an image signal line 261 is transferred to a secondcomb-shaped electrode 202 through a thin film transistor 263. As aresult, in-plane switching is performed between the second comb-shapedelectrode 202 and a first comb-shaped electrode 201 to which a commonvoltage is applied.

An electrically conductive layer constituting the first comb-shapedelectrode 201 is formed on a substrate 210 composed of glass orinsulator. As an alternative, the electrically conductive layer may beformed on the substrate 210 with an insulating film being sandwichedtherebetween.

In fabrication of the liquid crystal display in accordance with thethird embodiment, as illustrated in FIG. 13A, the first comb-shapedelectrode 201 is first formed on the substrate 210. Then, an interlayerinsulating film 211 is deposited over the first comb-shaped electrode201 and the substrate 210. Then, the second comb-shaped electrode 202 isformed on the interlayer insulating film 211.

Thereafter, there can be obtained various structures as illustrated inFIGS. 13B to 13E by implementing fabrication steps as follows.

The structure illustrated in FIG. 13B is characterized in that theinterlayer insulating film 211 is designed to have a first thickness ofa portion of the interlayer insulating film 211 formed on the firstcomb-shaped electrode 201, and a second thickness of a portion of theinterlayer insulating film 211 formed below the second comb-shapedelectrode 202, and that the first thickness is smaller than the secondthickness.

In order to obtain the structure illustrated in FIG. 13A, the followingsteps are implemented. First, a metal layer is deposited on either thesubstrate 210 or an insulating film formed on the substrate 210 by meansof a sputtering apparatus. Then, the metal film is patterned into thefirst comb-shaped electrode 201 and the scanning line 262 in aphoto-mask step.

Then, the interlayer insulating film 211 is deposited over the firstcomb-shaped electrode 201, the scanning line 262, and the substrate 210.After the thin film transistor 263 has been fabricated, a metal layer isdeposited by means of a sputtering apparatus. Then, as illustrated inFIG. 13A, the metal layer is patterned into the second comb-shapedelectrode 202 in a photo-mask step, and thereafter, the interlayerinsulating film 211 is recessed in the same photo-mask step.

The interlayer insulating film 211 is recessed, for instance, by etchingthe interlayer insulating film 211 with the second comb-shaped electrode202 being used as a mask, or etching the interlayer insulating film 211with photoresist having been used for forming the second comb-shapedelectrode 202, remaining on the second comb-shaped electrode 202.

A liquid crystal cell including the structure illustrated in FIG. 13Bensures that the flexo-electric effects found above the first and secondcomb-shaped electrodes 201 and 202 are balanced to greater degree than aliquid crystal cell in which the interlayer insulating film 211 does nothave the first thickness on the first comb-shaped electrode 201, whichis smaller than the second thickness below the second comb-shapedelectrode 202.

A structure illustrated in FIG. 13C can be obtained by further scrapingthe interlayer insulating film 211 until an upper surface of the firstcomb-shaped electrode 201 appears.

A structure illustrated in FIG. 13D can be obtained by further scrapingthe interlayer insulating film 211 until upper and side surfaces of thefirst comb-shaped electrode 201 appear.

The structures illustrated in FIGS. 13C and 13D ensure that theflexo-electric effects found above the first and second comb-shapedelectrodes 201 and 202 are balanced to greater degree than the structureillustrated in FIG. 13B. However, in the structures illustrated in FIGS.13C and 13D, there are formed steps at or in the vicinity of thecomb-shaped electrodes. It is considered that such steps exert harmfulinfluence on alignment of liquid crystal, and hence, it would benecessary to determine optimal degree of scraping the interlayerinsulating film 211.

A cover insulating film formed over the structure illustrated in FIG.13A, 13B, 13C, or 13D would ensure that the flexo-electric effects foundabove the first and second comb-shaped electrodes are relieved,resulting in more stable balance in flexo-electric.

For instance, FIG. 13E illustrates a liquid crystal cell including thestructure illustrated in FIG. 13A and a cover insulating film 212deposited over the structure of FIG. 13A.

In the liquid crystal display in accordance with the third embodiment,the interlayer insulating film 211 electrically separates the firstcomb-shaped electrode 201 from the second comb-shaped electrode 202,ensuring that the first and second comb-shaped electrodes are notelectrically short-circuited with each other, even if the first andsecond comb-shaped electrodes include patterning defects.

In addition, since it is not necessary to add a photo-mask step forscraping the interlayer insulating film 211, the number of fabricationsteps is not increased.

[Fourth Embodiment]

FIGS. 14 and 15A to 15D illustrate a liquid crystal display inaccordance with the fourth embodiment. FIG. 14 is a top plan view of apixel in the liquid crystal display, FIG. 15A is a cross-sectional viewtaken along the line XV--XV in FIG. 14, illustrating a step in a methodof fabricating the liquid crystal display in accordance with the fourthembodiment, and FIGS. 15B to 15D are cross-sectional views taken alongthe line XV--XV in FIG. 14, illustrating possible structures of theliquid crystal display in accordance with the fourth embodiment.

With reference to FIG. 14, when a scanning line 362 is selected, avoltage on an image signal line 361 is transferred to a secondcomb-shaped electrode 302 through a thin film transistor 363. As aresult, in-plane switching is performed between the second comb-shapedelectrode 302 and a first comb-shaped electrode 301 to which a commonvoltage is applied.

The fourth embodiment is characterized by that an interlayer insulatingfilm is recessed in a photo-mask step other than a photo-mask step inwhich the second comb-shaped electrode 302 is formed.

Similarly to the first to third embodiments, since an interlayerinsulating film 311 electrically separates the first comb-shapedelectrode 301 from the second comb-shaped electrode 302, ensuring thatthe first and second comb-shaped electrodes are not electricallyshort-circuited with each other, even if the first and secondcomb-shaped electrodes include patterning defects.

In a process for fabricating a liquid crystal display in accordance withthe fourth embodiment, as illustrated in FIG. 15A, the first comb-shapedelectrode 301 is first formed on a substrate 310. Then, an interlayerinsulating film 311 is deposited over the first comb-shaped electrode301 and the substrate 310. Thereafter, the second comb-shaped electrode302 is formed on the interlayer insulating film 311.

After formation of the second comb-shaped electrode 302, a photoresistlayer 351 is formed and patterned on the interlayer insulating film 311in a photo-mask step. Then, the interlayer insulating film 311 is etchedin a recessed region 350 with the photoresist layer 351 being used as amask.

A step for scraping the interlayer insulating film 311 by using thephotoresist layer 351 as a mask may be carried out before the formationof the second comb-shaped electrode 302.

FIGS. 15B to 15D illustrate examples of the thus obtained structures.The interlayer insulating film 311 is recessed in the recessed region350.

In the structures illustrated in FIGS. 15C and 15D, the interlayerinsulating film 311 and the substrate 310 are recessed to greater degreethan the structure illustrated in FIG. 15B. Hence, an advantage ofbalancing flexo-electric effect is enhanced in the structuresillustrated in FIGS. 15C and 15D to greater degree than the structureillustrated in FIG. 15B.

In accordance with the fourth embodiment, a step formed below sidesurfaces of the second comb-shaped electrode 302 is gentler than a stepformed below side surfaces of the second comb-shaped electrode 202 inthe second embodiment. As a result, it is possible to reduce harmfulinfluence on alignment of liquid crystal, caused by such a step.

In addition, since it is possible to distinguish the thin filmtransistor 363 from the recessed regions 350, the liquid crystal displayin accordance with the fourth embodiment can operate without exerting aninfluence on a structure and performance of a thin film transistorunlike the second embodiment.

It should be noted that the interlayer insulating film 311 may berecessed in the recessed regions 350 in a step in which other parts orelements of the liquid crystal display are also patterned. For instance,the interlayer insulating film 311 may be recessed in a step in which awiring layer is also formed, or a contact hole is also formed forelectrically connecting electrodes to each other, ensuring a higherefficiency in a fabrication process.

Similarly to the above-mentioned embodiments, a cover insulating filmsuch as the film 212 illustrating in FIG. 13E may be formed over thestructure illustrated in FIGS. 15B, 15C, or 15D.

[Fifth Embodiment]

FIGS. 16 and 17 illustrate a liquid crystal display in accordance withthe fifth embodiment. FIG. 16 is a top plan view of a pixel in theliquid crystal display, and FIG. 17 is a cross-sectional view takenalong the line XVII--XVII in FIG. 16.

With reference to FIG. 16, when a scanning line 462 is selected, avoltage on an image signal line 461 is transferred to a firstcomb-shaped electrode 401 through a thin film transistor 463. As aresult, in-plane switching is performed between the first comb-shapedelectrode 401 and a second comb-shaped electrode 402 to which a commonvoltage is applied.

In a process for fabricating a liquid crystal display in accordance withthe fifth embodiment, as illustrated in FIG. 17, the first comb-shapedelectrode 401 is first formed on a substrate 410. Then, an interlayerinsulating film 411 is deposited over the first comb-shaped electrode401 and the substrate 410. Thereafter, the second comb-shaped electrode402 is formed on the interlayer insulating film 411.

In the fifth embodiment, the second comb-shaped electrode 402 iscomprised of a comb-shaped electrode 402a composed of metal and ananodic oxide film 402b covering the comb-shaped electrode 402atherewith. The anodic oxide film 402b is formed by implementing anodicoxidation to a metal film after the metal film has been patterned intothe second comb-shaped electrode 402.

The liquid crystal display in accordance with the fifth embodiment issimilar in structure to the liquid crystal display in accordance withthe second embodiment, but is different in that the comb-shapedelectrode 402a is covered at upper and side surfaces thereof with theanodic oxide film 402b. This ensures that the flexo-electric effect isrelieved also at a side surface of the second comb-shaped electrode 402.

Though not illustrated, the fifth embodiment may be combined to thethird or fourth embodiment That is, in the combined embodiments, thesecond comb-shaped electrode 420a is covered at upper and side surfacesthereof with the anodic oxide film 420b, and the interlayer insulatingfilm 411 is formed with the recessed region 350.

Similarly to the above-mentioned embodiments, a cover insulating filmsuch as the film 212 illustrating in FIG. 13E may be formed over thestructure illustrated in FIG. 17.

[Sixth Embodiment]

FIGS. 18A to 18F illustrate a liquid crystal display in accordance withthe sixth embodiment. FIG. 18A is a cross-sectional view of the liquidcrystal display, illustrating a step in a method of fabricating theliquid crystal display in accordance with the sixth embodiment, andFIGS. 18B to 18F are cross-sectional views illustrating possiblestructures of the liquid crystal display in accordance with the sixthembodiment.

The sixth embodiment is comprised of a combination of a structure wherea region in which a second comb-shaped electrode is to be formed is inadvance recessed, and the structure of one of the first to fifthembodiments.

In a process of fabricating the liquid crystal display in accordancewith the sixth embodiment, as illustrated in FIG. 18A, a substrate 510or an insulating film formed on the substrate 510 is recessed to therebyform a recessed portion 550 in which a second comb-shaped electrode isto be formed.

FIG. 18B illustrates a structure obtained by combining the sixthembodiment with the first or second embodiment. That is, the secondcomb-shaped electrode 102 and the flexo-electric relieving layer 103formed on the second comb-shaped electrode 102 are formed on theinterlayer insulating layer 111 in the recessed portion 550.

FIG. 18C illustrates a structure obtained by combining the sixthembodiment with the third embodiment. That is, the second comb-shapedelectrode 202 is formed on the interlayer insulating film 211, and theinterlayer insulating film 211 is designed to have a first thicknessabove the first comb-shaped electrode 201 and a second thickness belowthe second comb-shaped electrode 202. The first thickness is smallerthan the second thickness.

FIG. 18D illustrates a structure obtained by combining the sixthembodiment with the fifth embodiment. That is, the second comb-shapedelectrode 402 is formed on the interlayer insulating film 411 in therecessed portion 550, and the second comb-shaped electrode 402 iscomprised of a comb-shaped electrode 402 and an anodic oxide film 402bcovering the comb-shaped electrode 402a therewith.

The liquid crystal display in accordance with the sixth embodiment ischaracterized in that the first comb-shaped electrode is designed tohave an upper surface which is level with an upper surface of the secondcomb-shaped electrode. This ensures that the first and secondcomb-shaped electrodes are not short-circuited with each other, that theflexo-electric effects found above the first and second comb-shapedelectrodes are balanced, and that there can be obtained a horizontalelectric field ideal for in-plane switching.

The structure where the first and second comb-shaped electrodes are ofthe same height ensures that the flexo-electric effects found above thefirst and second comb-shaped electrodes can be balanced, even if aninsulating film 513 is formed over the structure illustrated in FIG. 18Bfor flattening an upper surface of a liquid crystal cell, as illustratedin FIG. 18E.

The insulating film 513 may be formed, for instance, by depositingsilicon oxide or silicon nitride by means of a chemical vapor depositionapparatus, and polishing the silicon oxide or silicon nitride, orspin-applying a film composed of organic polymer such as polyimide,acrylate, or siloxane, and baking the film. The thus spin-applied filmmay double as an alignment film.

The insulating film 513 for flattening an upper surface of a liquidcrystal cell eliminates sharp steps on a surface with which a liquidcrystal layer makes contact, ensuring prevention of misalignment ofliquid crystal. In addition, the insulating film 513 relieves theflexo-electric effects generated on the first and second comb-shapedelectrodes, resulting in that enhancement of display performance andsuppression of generation of after-image.

The above-mentioned method of forming the insulating film 513 can beapplied to the above-mentioned first to fifth embodiments, if a firstcomb-shaped electrode is designed to have an upper surface level with anupper surface of a second comb-shaped electrode.

In the structure illustrated in FIG. 18E, the flexo-electric relievinglayer 103 to be formed directly on the second comb-shaped electrode 102may be omitted, if a capacitance per a unit area, of a dielectric layerformed between an upper surface of the first comb-shaped electrode and aliquid crystal layer is almost equal to a capacitance per a unit area,of a dielectric layer formed between an upper surface of the secondcomb-shaped electrode and a liquid crystal layer.

One of examples of such a structure is illustrated in FIG. 18F. Byomitting the flexo-relieving layer 103, a process for fabricating thestructure illustrated in FIG. 18F can be simplified relative to aprocess for fabricating the structure illustrated in FIG. 18E.

A step for forming the recessed portion 550 in the sixth embodiment maybe in common with other step for forming other part of a liquid crystaldisplay. For instance, a step for forming the recessed portion 550 maybe in common with a step for forming a contact hole, resulting in ahigher efficiency in a fabrication process.

While the present invention has been described in connection withcertain preferred embodiments, it is to be understood that the subjectmatter encompassed by way of the present invention is not to be limitedto those specific embodiments. On the contrary, it is intended for thesubject matter of the invention to include all alternatives,modifications and equivalents as can be included within the spirit andscope of the following claims.

The entire disclosure of Japanese Patent Application No. 9-356527 filedon Dec. 25, 1997 including specification, claims, drawings and summaryis incorporated herein by reference in its entirety.

What is claimed is:
 1. A liquid crystal display comprising:(a) a firstsubstrate; (b) a second substrate spaced away from and facing said firstsubstrate; (c) a liquid crystal layer sandwiched between said first andsecond substrates; (d) a first electrode formed on said first substrateat a surface facing said liquid crystal layer; (e) a second electrodeformed on said first substrate at a surface facing said liquid crystallayer, and cooperating with said first electrode to form a pixel, saidfirst and second electrodes generating an electric field therebetween tothereby implement in-plane switching; and (f) an interlayer insulatingfilm formed at least below said second electrode, but not formed atleast below said first electrode, said interlayer insulating filmcontaining at least one recessed region other than a region locatedbelow said second electrode, a dielectric layer formed between at leasta part of an upper surface of said first electrode and said liquidcrystal layer being designed to have a capacitance per a unit area,almost equal to a capacitance per a unit area of a dielectric layerformed between at least a part of an upper surface of said secondelectrode and said liquid crystal layer.
 2. The liquid crystal displayas set forth in claim 1, wherein said interlayer insulating film coverssaid first electrode therewith, and said interlayer insulating film isdesigned to have a first thickness on an upper surface of said firstelectrode and a second thickness below said second electrode, said firstthickness being smaller than said second thickness.
 3. The liquidcrystal display as set forth in claim 2, wherein said interlayerinsulating film is designed to have a third thickness in a region, saidregion located on either side of said first or said second electrode,but not below said second electrode, and said third thickness beingsmaller than said second thickness.
 4. The liquid crystal display as setforth in claim 1, further comprising a cover insulating film coveringsaid first and second electrodes therewith.
 5. A liquid crystal displaycomprising:(a) a first substrate; (b) a second substrate spaced awayfrom and facing said first substrate; (c) a liquid crystal layersandwiched between said first and second substrates; (d) a firstelectrode formed on said first substrate at a surface facing said liquidcrystal layer; (e) a second electrode formed on said first substrate ata surface facing said liquid crystal layer, and cooperating with saidfirst electrode to form a pixel, said first and second electrodesgenerating an electric field therebetween to thereby implement in-planeswitching; (f) an interlayer insulating film formed only in a regionother than an upper surface of said first electrode, and (g) adielectric layer formed between at least a part of an upper surface ofsaid first electrode and said liquid crystal layer being designed tohave a capacitance per a unit area, almost equal to a capacitance per aunit area of a dielectric layer formed between at least a part of anupper surface of said second electrode and said liquid crystal layer. 6.The liquid crystal display as set forth in claim 1, wherein saidelectrically insulating material is an anodic oxide film.
 7. A liquidcrystal display comprising:(a) a first substrate; (b) a second substratespaced away from and facing said first substrate; (c) a liquid crystallayer sandwiched between said first and second substrates; (d) a firstelectrode formed on said first substrate at a surface facing said liquidcrystal layer; (e) a second electrode formed on said first substrate ata surface facing said liquid crystal layer, and cooperating with saidfirst electrode to form a pixel, said first and second electrodesgenerating an electric field therebetween to thereby implement in-planeswitching; (f) an interlayer insulating film formed at least below saidsecond electrode, but not over an upper surface of said first electrode;and (g) a dielectric layer formed between at least a part of an uppersurface of said first electrode and said liquid crystal layer beingdesigned to have a capacitance per a unit area, almost equal to acapacitance per a unit area of a dielectric layer formed between atleast a part of an upper surface of said second electrode and saidliquid crystal layer.
 8. A liquid crystal display comprising:(a) a firstsubstrate; (b) a second substrate spaced away from and facing said firstsubstrate; (c) a liquid crystal layer sandwiched between said first andsecond substrates; (d) a first electrode formed on said first substrateat a surface facing said liquid crystal layer; (e) a second electrodeformed on said first substrate at a surface facing said liquid crystallayer; and cooperating with said first electrode to form a pixel, saidfirst and second electrodes generating an electric field therebetween tothereby implement in-plane switching; (f) an interlayer insulating filmformed at least below said second electrode, but not over upper and sidesurfaces of said first electrode; and (g) a dielectric layer formedbetween at least a part of an upper surface of said first electrode andsaid liquid crystal layer being designed to have a capacitance per aunit area, almost equal to a capacitance per a unit area of a dielectriclayer formed between at least a part of an upper surface of said secondelectrode and said liquid crystal layer.
 9. A method of fabricating aliquid crystal display comprising: (a) a first substrate; (b) a secondsubstrate spaced away from and facing said first substrate; (c) a liquidcrystal layer sandwiched between said first and second substrates; (d) afirst electrode formed on said first substrate at a surface facing saidliquid crystal layer; and (e) a second electrode formed on said firstsubstrate at a surface facing said liquid crystal layer, and cooperatingwith said first electrode to form a pixel, said first and secondelectrodes generating an electric field therebetween to therebyimplement in-plane switching,said method comprising the steps, insequence, of:(a) forming a first metal layer on said first substrate;(b) patterning said first metal layer into a first electrode; (c)covering said first electrode with an interlayer insulating layer; (d)forming a second metal layer on said interlayer insulating layer; and(e) etching both said second metal layer and said interlayer insulatinglayer to thereby pattern both said second metal layer and saidinterlayer insulating layer into said second electrode, and thin orremove said interlayer insulating layer in a region other than a regionlocated below said second electrode.
 10. The method as set forth inclaim 9, wherein said liquid crystal display further comprises aninsulating film formed on said first substrate, and wherein said firstmetal layer is formed on said insulating film.